Steam-boiler.



PATENTED AUG; 18, 1903.

M. OCONNOR.

STEAM BOILER.

APPLICATION FILED JAN. 10. 1903.

NO MODEL.

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No. v3e,e21.

Patented August 18, 190a.

ATENT FFICE.

STEAM-BOILER.

SPECIFICATION forming part of Letters Patent No. 736,621, dated August18, 1903.

Application filed January 10,1903. Serial No. 138,500. (No model.)

To all whom it may concern.-

Be it known that 1, MICHAEL OCoNNoR, a citizen of the United States,residing at Missouri Valley, in the county of Harrison and State ofIowa, have invented a new and useful Steam-Boiler, of which thefollowing is a specification. I A

In the construction of steam-boilers, and more particularly thoseemployed in locomotives, great difficulty has been experienced inpreventing cracking and leakage about the door of the fire-box. As iswell known, the wall is composed of an outer and an inner sheet havingoverlapping flanges that surround the door-opening. The outstandingflange carried by the inner door-sheet is disposed at substantiallyright angles thereto, and the connection of said flange with the sheetis in the form of a sharp bend or knuckle in the metal. It is with thisportion of the structure that the difficulty is experienced, as thecracks occur along this inner knuckle. There are several reasons thatcooperate to cause the damage. In the first place the inner door-sheetand flange are highly heated by the fire in the box; but as soon as thedoor is opened by the fireman a great volume of cold air rushes throughthe doorway, this inrush being caused by the powerful exhaust of thelocomotive. As a result the flange and knuckle are suddenly cooled,causing unequal and instantaneous contraction of the metal, thus settingup strains which tear the flange away from the sheet. This unequalexpansion and contraction is furthered by the fastening of the shortflanges together, said'flanges thus being more rigid than the remainderof the sheets and being of smaller area, so that they are incapable ofas relatively great movement. Another objectionable feature resides inthe very limited body of water which has heretofore surrounded thedoorway. The space is so contracted by the overlapping flanges and theheads of the rivets fastening the same that very little water can comeinto direct contact with the outwardly-extending flange. Moreover, inthis small space incrustation and deposits of foreign matter sooncollect, thus separating the water entirely from the metal andpermitting said metal to become overheated, thereby assisting in theinjury above described. As a result of these various destructiveagencies it is a very common thing to have a ruined door-sheet in apractically new fire-box, necessitating the withdrawal of the locomotivefrom service and requiring expensive repairs. I

Now it is the object of this invention to entirely obviate thisobjectionable feature by providing an improved structure which willfreely expand and contract without causing undue strain and at the sametime obtaining a sufficiently-enlarged water-chamber about the doorwayto prevent to a very great degree accumulations therein. The structureby which these objects are attained is very simple and is no moreexpensive than that heretofore employed. Furthermore, itdoes not requirea radical departure of any kind in the general shape or construction ofthe boiler.

The preferred and what has proven to be an entirely practicableembodiment of the invention is illustrated in the accompanying drawingsand is described in the'following specification.

In said drawings, Figure 1 is a sectional view through the fire-box of alocomotiveboiler. Fig. 2 is an elevation of the inner door-sheet.

Similar reference-numerals indicate corresponding parts in both figuresof the drawings.

The boiler, or the portion herewith illusstrated, is of the usualwell-known type, having an outer shell 10 and a fire-box 11. Theinvention relates solely to the rear wall of the boiler, which isdesignated as a whole by the reference numeral 12. This wall has theusual door-opening therethrough, and is composed of an outer sheet 13and an inner sheet 14, spaced apart and connected by stay-bolts 15. Thesheets are provided with oppositelyextending overlapping flanges 16 and17, which thus form the door-opening,said flanges being fastenedtogether by rivets 18. Instead of the usual sharp bend or knucklebetween the flange 17 and the inner sheet 14 the portions of the metalconnecting said flanges and sheet are inwardly swelled, as shown at 19,this swelling thus forming a circular and inwardly-convexed boss aboutthe door-openin g. As a result an enlarged water-chamber 20 is formed,which entirely surrounds said opening. While it will be apparent thatthis change does not involve any radical departure from the usualconstruction and that it can be easily made without additional expense,the advantages which are obtained are very important. In the first placethere is no comparatively sharp bend in the metal, while additional areais obtained. As a result, when the flange 17 is cooled during the inrushof cold air in the manner above described the swelled portion can freelycontract without any danger of cracking, as the pronounced curve in theinner sheet gives freely to the strains. A number of benefits arederived from the enlarged water-space 20. The comparatively large bodyof heated water tends to maintain a more even temperature of the metal,preventing to a great extent its being overheated, and also tending topreclude the too-rapid cooling of the flanges. Furthermore, it providesmore room about the inner heads of the rivets 18, and in this enlargedchamber there is not as much danger of the sediment accumulating andseparating the Water from the flanges. This feature is therefore ofespecial importance in locomotives runningin bad-water districts. Actualexperience has proven that the structure is entirely practicable andsatisfactory, and it has entirely obviated the objections noted in thepreliminary portion of the specification.

While the invention, as shown and described, is particularly useful inlocomotiveboilers, it will be readily understood by those skilled in theart that it is applicable to boilers of different types, and theinvention is not limited to this one class.

From the foregoing it is thought that the construction, operation, andmany advantages 0f the herein-described invention will be apparent tothose skilled in the art without further description, and it will beunderstood that various changes in the size, shape, proportion, andminor details of construction may be resorted to without departing fromthe spirit or sacrificing any of the advantages of the invention.

Having thus fully described my invention,

what I claim as new, and desire to secure by Letters Patent, is-

1. In a boiler, a fire-box Wall comprising spaced sheets having adoor-opening therethrough, the portion of one of the sheets surroundingthe opening being swelled or enlarged to provide additional expansiveand contractive surface.

2. In a boiler, an outer fire-box wall having an inner sheet, said wallbeing provided with a door-opening extending through the inner sheet,the portion of the inner sheet about the door opening being inwardlyswelled or enlarged.

3. In a boiler, a fire-box wall having an opening therethrough, saidwall comprising spaced sheets, the portions of said sheets that surroundthe door-opening being spaced farther apart than the remaining portionsto provide a water space or chamber of greater area. 1

4:. In a boiler, a fire-box wall having an opening therethrough, saidWall comprising spaced sheets, having oppositely-extending flangessurrounding the opening and located in overlapping relation, theportions connecting the flange and the inner sheet being swelledinwardly and curved, thereby providing an enlarged Water-chamber aboutthe opening.

5. In a boiler, a fire-box wall having a dooropening therethrough andcomprising an outer and an inner sheet, said outer sheet having aninwardly-extending flange that surrounds the opening, the inner sheethaving an outwardly-extending flange that overlaps and is secured to theflange of the outer sheet, the portion of the inner sheet forming theconnection with the flange thereof being inwardly swelled and forming anenlarged water-chamber.

In testimony that I claim the foregoing as my own I have hereto affixedmy signature in the presence of two witnesses.

MICHAEL OOONNOR.

Witnesses:

M. J. BUsHE, W. D. CODY.

